Jones previously served time after being convicted for the killing of 15-month-old Chelsea McClellan. She was sentenced to 99 years in prison in 1984, but would have been released in 2018 because of a state law meant to relieve prison overcrowding.
Prosecutors filed new charges in 2017. At the time, former Bexar County District Attorney Nico LaHood said evidence showed Jones killed Joshua Sawyer with a deadly dose of Dilantin while he was a patient at Bexar County Hospital in San Antonio, now called University Hospital.
That explains things a bit to me. She was first convicted in 1984. They pressed new charges to avoid letting her out of prison.
As for death penalty, there are hurdles the DA needs to jump through to get a death penalty verdict and it was likely a lot easier to get this conviction. The automatic appeals would be expensive as well.